How do I get a 930 to handle like a 911?
 

Gents,

In a turn or when cornering, my 930 has a "heaviness" to it that my 911 doesn't and I want my 930 to perform like the 911. In all, it comes down to the 911 being more nimble in a turn than the 930.

How do I get my 930 to do the same? What equipment or changes can be made to improve it?

My 911 has newer OEM struts and shocks. Would that be the difference?

What are your alignment settings? specifically front caster. Too much caster angle will make the car really stable in a straight line yet will take away from the light steering and nimble feeling.

Jamie,

My front caster is 0.13 degrees on the 930 and I don't know what the 911 is. Is 0.13 degrees a setting that would cause it to be less nimble?

Most racy 911s use about 6-7 degrees caster because it makes the wheels lean into a turn for more grip. 0.13 degrees is hardly anything.

My 911 has no track history and from what I know of the previous owners they didn't make any changes. I haven't had the 911 aligned for the 5 years I have owned it. It drives great so I didn't see the need. With that said, would a 911 be different than the 0.13 degrees set on the 930?

some threads on caster where people talk about their values:

http://forums.pelicanparts.com/porsche-911-technical-forum/569002-3-2-carrera-sc-handling.html

http://forums.pelicanparts.com/porsche-911-technical-forum/561337-bump-steer-question.html

Weight, track (wheels are further outward than a 911), wider tires, are all contributing factors. The factory also set up the 930 to push in the turns to counter oversteer induced by sudden turbo onset.

Thanks for the thread links! I was looking at the difference all wrong. I was thinking it must be because of their body types. The real difference must be in their alignments.

It could be a lot of things combined. You might never get it to feel 'just right' if 'just right' is how your 911 feels. They are different vehicles when you look at the specs.

You can try adjusting the alignment and such on your 930 as long as you understand that you are attempting to make a 930 feel not like a 930, but like another car with a narrower track and different weight proportions and different stance, different tires, different power delivery, different suspension, ect.

You probably should look at it from the point of view of optimizing the 930's handling to be a more nimble 930. Trying to imitate a 911 might not be possible or ideal.

You probably want a more aggressive stance for the 930 so it turns sharper yet not so much that the rear comes around under power.

And its great question! Love to see how this turns out.

Are you sure you're talking about Caster, not toe?

One thing is also tire combo and tire pressures. It might feel better for you if the tires are NOT very staggered. Try 245 front 255 rear but that feels a bit oversteering for most people. I liked that setup though.

Here is what I have planned for the 930 in the coming months.

Will this get me further away or closer to the 930 turning like the 911?

My tires/rims are going from 205/16 front and 245/16 back to 235/17 front and 315/17 back.

The 911 has 205/16 front and 235/16 on the back

I'm planning to use the Elephant racing Street Perf 2 package:

Front:
Torsion Bar 21mm
Polybronze control arm bearing
Low-friction Control arm mounts
Strut inserts- Bilstein Sport
Strut brace

Back:
Torsion Bar 27 mm
Polybronze Spring plate
Rear shocks Bilstein Sport

I also misread the 930 alignment; the caster is 5.8 to 6.3 degrees. The toe is -.44 degrees.

The 930 carries a significant weight penalty over a normal 911, especially over the rear wheels, and moving backwards because the engine is heavier as well.

I don't know where you live, but even in So Cal here, I made due without the AC system(which on any 911/930 is a substantial amount of dead-weight from one of the car to the other.) Also, if you go this route, mount the battery in the smugglers box, since you want as much mass to be inside the wheel base, not outside(one reason why mid-engined cars handle so favorable).

Rear seats? Do you really need them? Spare wheel inside of nose? Unless you are going cross country, or a road-trip, and have AAA, do you need this?

Every pound you shave off the car is a pound that the engine will never have to accelerate again. Dead weight shaved off also is mass not having inertia to carry into corners, banking, etc.

And remember...every tweak you make in a suspension, engine, chassis comes at some cost in driveability, noise/vibration/harshness, so be careful what you wish for.

I'm trying. I have removed the entire AC and heat system, spare tire, rear and passenger seat, rear wiper motor, and have a smaller Optima battery. I'm thinking on mounting the battery in the smugglers box. The car is brutally fun to drive, but still doesn't have the nimbleness of the 911.

Even with all that I have done to the 930, it is no match for my 911 if running downtown or with areas with 90 degree turns. I know they are different cars with different abilities, but can a 930 be made to compete with a 911 without compromising its strengths?

You may want to take a second look at your t bar choice. I think 21/27 may add more understeer to the car, as I think you are adding higher rate to the front relative to the back than the stock rates. I think the stock rates were already adding some oversteer...

Somewhere on here is a chart with the various sizes of t bars and their relative ratios to stock. I searched but could not locate it for you. It is here, somewhere.

You may want to go 21/28 or 21/29. Or maybe not...

Good luck.

I think my 930 handles as well as my old targa did, so I think it is achievable.
It just feels a little different because the track is wider and there is more rubber on the road.

+1 on the torsion bar rethink.

930's have a better suspension geometry than 911's and a fair amount can be done with tires and alignment. (Tires can often be the softest link in your suspension chain.) To much toe in will slow turn in and should be zero pressed or 15min non pressed per factory spec I belive. AutoX racers run toe out for quicker turn in. Also, more front camber can help front bite.

Stiffer torsion bars are a great upgrade.

However, for a 930 22mm front's are about right for a street / sport car. 21's are more for a light early car like a pre 74. 23's start to get on the serous side for the street.

For the rear, the 930 seems to need to go up one size over what a 911 might run with its heaver rear balance and limited slip. Thus a 30mm rear bar would probably be a good balance. This probably makes your car's wheel rate about 40% stiffer I would guess. (I can double check if you wish.)

New or upgraded bushings, a good sport alignment and corner ballance and you should have a very nimble car.

If you want to go one step up you might consider having the front spindle's raised on the front struts about 30mm and add a bump steer kit. This will greatly improve your front camber curve, make it better match to the 930's rear camber curve. More importangly it will help the front tires bite better in a corner.

First of all I would check alignment on both the 911 and the 930.

Secondly for a lower cost handling fix/adjustability add a adjustable rear swaybar, that way you can tune the over-understeer a fair bit.

The Elephant mods will make a big difference for sure but as others have said with 21 front bar you will need a bigger rear bar than the 27 to make the car more nimble than stock and I would go with 30mm rear maybe 29.

(Run 22/31 in my 930 and its perfectly neutral, a perfect road/track compromise. For autocross / slower tracks 22/32 would be perfect but I need my car to be stable enough for highspeed tracks.)



http://forums.pelicanparts.com/uploa...1289959167.jpg

I don't think much bigger tires, stiffer suspension and shocks will make the car more nimble. I don't even recommend Bilstein sports unless you get them custom dampened, they are way too stiff over potholes IMO. The dampening just isn't good. Several shops will sell them with better dampened inserts however.

If you want the car to turn sharper it will need a more aggressive stance/rake but to make it feel like a different car is going to be tough. It would be simpler to optimize how your 930 feels than try to make it a 911.

What's your budget?

I'm willing to spend what it takes to do it right, but I like to be educated before I spend a dime.

Agreed and from what you guys have been telling me it is possible to optimize my 930 to be more exciting. In the end, I may not match the 911. If I can get closer or make me want to drive the 930 on sharper roads then I have won!

Now, I'm really pumped about upgrading the suspension and alignment.

I know bigger tires will not make it more nimble, but I'm really exciting about the Toyo R888s that will be on my new rims. These tires look great and from what I read they handle very well.

Guys, I writing down all your ideas so when I update the suspension I don't lose your wisdom. Thanks.:)

I've got a set of Fuchs 3 pc 8x17 & 11x17 wheels and Goodyear 245/35/17 fronts, 315/35/17 rear F1 GS-D3 tires off my turbo I'm selling if your interested. Roonuts : Categories: Wheels & Tires

I tried to find those tires, but the 315s are on back-order until January. I've already ordered the Toyo R888s. Thanks for the offer.

What is your budget? ;) What kind of handling do you like? (quick and light I would think) :) What kind of bump isolation do you need?

Lots of goodies here, from the simple A-arm bushings to raised spindles, 935 suspension, coil-over springs, etc.

Suspension1

Dave at TRE motorsports might be a good one to talk to about your shocks. Even bilstein heavy duty shocks are rumoured to have better dampening than bilstein sport shocks.

He also knows about setting up 911 versus 930s.

Do you know any top notch shops in your area that will do alignments and corner balancing? It sounds like you do some work yourself?

Right now, I have no idea what bump isolation is. I need to look up what bump isolation means. Sorry, I'm still learning.

Quick and light sounds good and I like Rebel racing. The only reason I mentioned Elephant Racing is Elephant has that simple spreadsheet of products that they generate based where you drive. i.e track, street.

I'm not worried about budget or the prices of Rebel racing or Elephant.


TRE is a long way from South Carolina, but I wish they were closer. I have to go to Charlotte or Atlanta for alignment. Yes, we do the work ourselves on most projects. I'm not sure without a lift, if we could do the suspension. I want to collect the parts and then take it someone like Zuffenhaus in Charlotte to put it on and then align it.

I would have a lift, but our garage sits on a 4 percent decline. Don't feel safe with that.

By bump isolation I meant how much you feel bumps going over bad pavement. If you have smooth roads or don't mind feeling every line on the road, you can go for stiffer torsion bars and dampers. The bearings like Rebel Racing bearings do not add "harshness" on their own, because they remove a lot of friction from the system and allow the torsion bars and dampers to do their job smoothly without binding. They actually make the torsion bars effectively a bit softer.

I wonder if it can be done. They really feel like completely different cars to me and not just the same body with slightly different suspension geometry.

[QUOTE=PorscheGAL;5679966]I'm not sure without a lift, if we could do the suspension.[QUOTE]

You can do it without a lift. I just went through this and basically did Elephant's street performance 2 package. I changed everything except for the sway bars which remain stock. 22/29 torsion bars, polybronze bushings all around, off the shelf bilstein sports.

A dirty, pain in the @$$ job, but doable in the garage with hand tools. Took the car to a shop for the alignment and corner balance.

I'm very happy with the set up.

Another thing to consider...I made my 911SC into a 911 Turbo, via a 1986 930 engine(and a whole lot of green).

When I think back of how it USED to handle, and how it drives now, it's a totally different animal. As you say, brutally fast, yet as Thomas Wolf stated "you can't go back home", or something to that degree. I don't believe I'll ever get my 911 to now handle like a 911 again since the transformation. I just can't imagine getting a 930 to hustle around corners like a much better balanced 'normal' 911, anymore than you can get a normal 911 to hustle around a corner like a Miata, regardless of how much $$$ you plunk down(unless your building a track-car that will be driven on a pool-table surface. I don't know about you, but I drive my car all year around in the real world.


The 912 was praised upon how balanced it handled(and of course it was a 911 with a 4-banger). When Mercedes went from a 3.0L to a 3.2L between 1992-1993, even it's handling suffered with just .2L increase(sans turbo/intercooler/extra plumbing, etc.)

My thinking is, this will be an expensive lesson in futility without a MASSIVE reduction in weight behind the rear axle.

My 2-cents...

Yes, it is the lesson in futility part that we want you to avoid.

There are some ways to make it a great handling 930 however...

:)

Thinking aloud: could throttle response be part of the difference? Gear ratios?

Why would an SC with a 930 powerplant handle differently than an SC? Just ditch some cantilevered weight. The only difference is that it is capable of transferring weight faster now. Mine handles the same as it did before it had a turbo.

[QUOTE=jwasbury;5681007][QUOTE=PorscheGAL;5679966]I'm not sure without a lift, if we could do the suspension. I read your thread and that is when I started planning for the suspension upgrade. Your garage floor looks flat; mine is not. Also, I would have to drive or transported 2 hours to get my alignment done. even if I did the work myself. The Porsche dealer and other shops cannot align my car(s). :( I don't feel good about driving the car that far without alignment.

Didn't you make a comment in your thread about your 930 hanging with a friend's 911 when cornering?


yes, but I've tried to study those differences when driving and the 911 is unique in cornering against the 930. Maybe they are working in all instances to make the 911 more nimble?

I have always wondered if that was true! I bet that is fun to drive :D

How "un-level" is that garage floor? I did the suspension one end at a time. Raised the rear on stands and completed removal and installation of new parts, put the rear down and moved on the the front. If you can jack either end of your car up in your garage, I'd think you can do the necessary work. I roughed in the ride height, but did next to nothing for the alignment. It was a 20-30minute snooze cruise to the shop, and the car felt fine. The only thing I made sure of was to match the new tie rods up with the old as far as adjustment. That way you know the steering won't be totally wacked out. If you're more careful (and anal) than I was, you could mark the exact position of the ecentric toe and camber adjustment bolts on the rear and the position of the spring plate on the trailing arm (use a sharpie). Then when you reassemble, put these pieces back as you found them and you probably won't be far off on alignment.

My buddy with the 911 made a comment about how before my suspension refresh it was easy for him to follow me (even with only 1 hand on the wheel) and after he needed "both hands"

The ONLY way a 911SC would handle as it did before a turbo would to turbocharge the original 3.0L, with no intercooler, etc(which is a minimal addition of weight). I didn't go that route since the original 3.0L in my car was not designed from the factory for forced induction, so I just shelled out the $$$ for the real deal, a 930 engine.

The factory 3.3L Turbo engine was significantly heavier than the factory 3.0L normally aspirated engine. If the engine were in FRONT of the rear wheels(as in mid-engined), this would be desirable.

The best handling cars typically have as MUCH mass within the wheel-base, not at opposite ends(and the 911 design has a huge lump hanging off that rear-end outside the wheel base).

Coming back from Canada, I loaded up a ton of oak/cherry wood in the nose of my 911, and proceeded back to LA. One might think that this would nicely balance out the rear weight on the back....not so. At triple digit speeds, the car was becoming very scary at triple-digit speeds in the corners/banking trying to launch me into the scenery.

If anyone has the stats on a normal weight of a 3.0L engine versus a 3.3 Turbo engine, I would like to know, but I am betting somewhere on the order of 1 to 1.5 bags of concrete(100lbs/bag) difference between the two engines. Sure made a big difference between my old 911 and the same 911 now with a 3.3

I did turbo the 3.0 in the SC. So, you hang some extra weight off the rear with the turbo, but I subtracted a lot by ditching the AC, smog pump, etc. The rear rubber bumperettes weigh 8 pounds each. I have a water injection system, and no air side intercooler. I doubt the engine weight difference between 3.3 turbo and 3.0 na is 100-150 lbs, but I could be wrong. I too would like to know exactly what the difference is.

My SC weighs 2570 lb, with a roll bar. It has really good corner balance (I forgot the numbers at this moment), but it is balanced for braking bias. It is a street car which I track.

When I first bought the car, I ripped out all of the suspension and rebuilt it. Everything. That was the biggest difference in handling. 21/27 bars, stock sway bars, Elephant polybronze in the front, turbo tie rod ends, rebuilt steering rack, new rear bushings, new sway bar bushings, Bilstein Sports all around. The SC has always handled well since this refresh.

Back to Steph's original question...a 930 IS a 911. A bit wider, better brakes, essentially the same car. Porsche didn't make this an inferior handling package from the factory; it was likely every bit as good if not better. You need to refresh the suspension package. Handling is the single virtue of the 911/930, in fact, all Porsches. My Boxster and 968 are both great handling cars, but neither has the beastly go fast handling ability of the 911.

I am just guessing--

The 3.3 turbo 930 has the motor mounted about 1.5" more rear-wards. That probably has as much to do with its greater rear-wards bias as anything. It also has a heaver transmission and typically a LSD that can fight the car in a turn.

Put it in an SC behind a 915 transmission and it should be in the same place as the SC's.

The 3.0SC and 3.3 turbo motors mostly differ as to the weight of a turbo its self and the addition of an intercooler. Put a set of headers and straight through muffler on the 3.3 turbo motor and they are probably going to be close to the same weight.

Of course it probably dose not help at slow speeds having the extra 35 lbs from the spoiler hanging out back.

Being nimble probably has more to do with tire side wall profile / construction and alignment when comparing a 3.3 turbo body car to a narrow body car.

The other is the NA motor is usually much more responsive and has better gears making it easer to throttle steer it in a corner.

The 930 out of the box has a better geometry with lesser bump steer up front, more anti dive as the rear of the rear A arms are about 1/2 inch higher, and it has a higher roll center which lets it handle flatter with almost the same suspension wheel rates. It also has a little better camber curve in the front and a more aggressive camber curve in the rear. Plus the wide wheel base improves the angle of the center of gravity to the wheel contact patch.

Thus, it has the potential to out perform a narrow body if set up well.

K-
I did not realize the engine was back 1-1/2" in a 930. Do you know why this is? A function of the transaxle length?

In my case, the 3.0 had stock 8.5:1 Mahle pistons in it, so I had basically the same throttle response before and after the turbo. I just have more throttle to respond now:)

I agree the 930 will outperform a narrow body. I have seen some fast and nimble 930's at the track.

Going from the 3.0 turbo to the 3.3 they lengthened the bell housing to put in a bigger clutch.

Again, there are a bunch of other changes between the suspension's. I forgot the turbo comes with...... turbo tie rods from the factory!

What did they change to accommodate the width of the car?